The Trill Assembly was the state of the Trill people, with its seat on the planet Trill. (ST video game: Infinite)
The head of the government was called a President or Leader, while the legislature was called the Senate. Both were housed in the Trill Senate Tower, in the city of Leran Manev on Trill. (DS9 - Worlds of DS9 novel: Trill: Unjoined)
The Trill ruling council was divided into junior and senior members. Senior members, whose symbionts had lived more than one lifetime, were allowed to call general meetings. Junior members, whose symbionts had lived only one, were not. (DS9 short story: "First Steps")
History[]
Ruling council membership was restricted to joined men until the 21st century. (DS9 short story: "First Steps")
Trill joined the United Federation of Planets some time around the early 23rd century. (TNG novel: Intellivore)
In 3189, when the Federation uncovered the cause of the Burn and a vast supply of dilithium, Leader Pav travelled to the Federation Headquarters to meet Federation leadership. Trill became one of the first former Federation members to rejoin. (DSC episode: "That Hope Is You, Part 2")